Art of and apparatus for making figured surfaces



F. H. NORTON. ART OF AND APPARATUS FOR MAKING FIGURED SURFACES.

APPLICATION FILED AUG.'22, I919.

PatentedMar. 28, 1922.

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APPLICATION FILED AUG. 22. 1919.

Patented Mar. 28,

F. H. NORTON. ART OF AND APPARATUS FOR MAKING FIGURED SURFACES.

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ART OF AND APPARATUS FOR MAKING FIGURED SURFACES. APPLICATION FILED AUGJZ 1919.

1,410,591 Patented Mar; 28,

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ART- OF AND APPARATUS FOR MAKING FIGURED SURFACES.

' APPLICATION FILED AUG.22. 1919.

1,41 0,59 1. Patented Mar. 28, 1922.

:P 5 SHEETS-SHEET 5- Kigali air FREDERICK H. NORTON, OF LANGLEY FIELD, VIRGINIA.

ART OF AND APPARATUS FDR MAKING FIGURED SURFACES.

reiasei.

Specification of Letters Patent.

Patented Mar. 28, 11922.

Application filed August 22, 1919. Serial No. 319,120.

To all whom it may concern:

Be it known that I, FREDERICK H. Non- TON,- a citizen of the United States, and resident of Langley Field, in the county of Elizabeth City and State of Virginia, have invented new and useful Improvements in Art of and Apparatus for Making Figured Surfaces, of which the following is a specification.

This invention relates to an improved art of and apparatus for reproducing upon a blank of material a curved or figured surface whose co-ordinates are proportional to calculated theoretical values. The surfaces of pro-calculated geometric solids, in three dimensions, or the boundaries of curvededge areas may be produced by the new method and are characteristic products of the apparatus.

In designing aeroplanes, for instance, it

is customary after having calculated the curvature of the wing surfaces of a proposed machine, to construct a small model in which the calculated wing surfaces are accurately reproduced, and to test such model in a suitable wind tunnel in order to test its efliciency and to determine the advisability of continuing further development of the design and the incorporation of the design in a full sizevmodel for actual trial flight. Many such models are tried and compared. Heretofore, so far as I am aware, it has been customary to reproduce such model wing surfaces or aerofoils by extremely tedious handwork, the skilled mechanic carefully shaping the surface of the blank fromw'hich the aerofoil is to be made. to conform to the theoretical surface calculated by the designer. Even aslight change in figures implies long and skillful labor. When the aerofoil is made from wood the work is tedious, but when made from metal-the work is extraordinarily di'Hicult and slow, and many days are required to complete a single aerofoil. The same difficulties are incident to the careful design and model construction of other objects,sucli as model hulls, bodies, struts as well as full sized propellers and other screws, and the air and water guards and baflies'of nautical apparatus, automobiles, and pneumatic apparatus, and'in many other situations in which calculated figure of an edge or a solid surface is important.

An object of the present invention 18 to overcome the difiiculties heretofore encountered,.by practice of a new art of reproducing upon a blank a curved or figured edge or surface, such for example as the curved surface'of an aerofoil or aeroplane propeller whose co-ordinates are proportional to calculated theoretical values; and to provide a machine by aid of which the method or art may be practiced which is simple to operate, extremely accurate and which may be operated to form rapidly the desired surfaces. The invention therefore provides a machine which may be quickly and accurately adjusted in accordance with the calculated values of surface curvature and which when so adjusted is capable of guiding a suitable cutting tool over the surface of a blank, the cutting tool being given a motion'relative to the blank proportional to the movement imparted to a follower, stylus or guide member by its contact with an adjustable element of the machine.

The invention will now be described in connection with preferred forms of the genus of apparatus for practicing the method or art, and also comprised in the invention.

In the accompanying drawings,

Figure 1 is a front elevation of a ma chine illustrating one instance of the preferred apparatus;

Figure 2 is a plan view of the machine shown in Fig. 1;

Figure 3 is an end view as viewed from the right in Fig. 1;

Fi ure 4 is a detail view showin earing for driving the cutting tool;

Figureo is a detail view of gears for transmitting power to either one of two feed screws;

Figure 6 is a detail view showing the method of attachment of a small cutting tool to the main cutter spindle;

Figure 7 is a view showing the method of attachment of a small grinding wheel to the main cutter spindle;

Figure 8 is a detail view showing in elevation a portion ofthe adjustable template and the means by which it is adjusted;

Figure 9 is a vertical section on line 99 of'Fig. 8;

Figure 10 is a horizontal section on line 1010 of Fig. 9;

Figure 11 is a perspective view of one of the knife edges carried by a template adjusting rod for engagement with the tem plate;

Figure 12 is a diagrammatic view showin a modified form of machine for cutting a figured surface or a surface having double curvature Figure 13 is a view showlng the manner in which successive cuts may be taken by a machine such as is illustrated in Fig. 12;

Figure 1a is an end view corresponding to Fig. 13;

Figure 15 is a plan view showing a propeller blank mounted upon the carriageof the machine shown in'Fig. 1 in a position to be cut;

Figure16 is a section taken on line 1616 of Fig. 15, and

Figure 17 is a fragmentary end view partly in section from the left hand end of the machine illustrating certain driving connections.

Referring to the drawings and more. particularly to Figs. 1, 2 and 3, one embodiment of a machine suitable for cutting the surfaces ofmodel aerofoils or propellers is disclosed. The machine comprises a hollow base .or bed-casting 1 provided upon its upper face with longitudinally extending ways 2 and upon its front face with longitudinally extending ways 3'. Supported by trunnions 4 and trunnion blocks 5 upon one end of the base 1 is a beam 6. The trunnion blocks 5 are bolted to the base 1 by bolts 7, but may be adjusted vertically with respect to the base 1 by means of the adjustable wedge S which co-operates with the beveled under surfaces of the trunnion blocks 5. T he wedge 3 is traversable in suitable guides upon the top of base 1 and is traversed by means of a feed. screw 9 and hand wheel 10. To raise or lower the beam 6 relative to the base 1 itis only necessary to loosen the bolts 7 and traverse the wedge 8 either under or out from under the trunnion blocks. The trunnion blocks 5 are provided with extensions 11 which are kerfed as shown at 12, the kerfs extending downwardly into the trunnion openings and thus providing trunnion clamps which may be tightened by means of levers 13 to clamp the trunnions '4; from turning too easily.

The beam 6 is in the general form of a hollow box-shaped member and is provided near its left-hand end as viewed in Fig. 1 with vertically disposed fiangeslat carrying the trunnions 4;. The extreme left-hand end of the beam is formed asa substantially horizontal shelf orbracket 15 upon which the driving motor 16 is mounted and secured by stud bolts 17.- Journaled in bearings 18 in the lower edge of the beam 6 and midway of. its length is a cutter spindle 19 provided upon its rear end with a belt pulley 20' and upon its forward end with a suitable cutter 21. The cutter may be such as is suitable for cutting wood, or for cutting metal, or may be in the form of an abrasive wheel depending upon the nature of the work to be done.

Power is transmitted from the motor 16 to the spindle 19 by suitable transmission gearing or by a beltedfconnection as most clearly disclosed in Fig. 4:. A cone clutch 22 transmits power from the shaft 23 of motor 16 to the main transmission shaft 24 which is suitably journaled within the beam 6. The clutch comprises a drum member 25 secured to the motor shaft 23 as by a set screw 26 and a cone member 27 provided with a grooved collar 23. The cone member is splined to the shaft 24 in such manner as to permit the member to be moved longitudinally along the shaft to move the cone member into and out of engagement with the drum member 25, but to cause the cone member to partake of the rotary motion of the shaft 24. Mounted upon the shaft 24: is a V spiral gear 29 which through the spiral gear 30 transmits power to the vertically disposed shaft 31 for a purpose hereinafter described. Mounted uponthe shaft 24 are transmission gears 32, 33 and 34 which are adapted to mesh with gears 35, 36 and 37 respectively, slidably but non-rotatably mounted upon the horizontally disposed shaft 33. The gears 35 and 36 are integrally united to a grooved collar 39 and are slidably keyed to the shaft '33 by means'of'a key 41), and the gear 37 is secured to a grooved collar 11 which is also slidably keyed to the shaft 38 by thekey 40. The shaft 38 is geared to the auxiliary transverse shaft 42 journaled in any suitable manner within the beamfi above the spindle 19, by means of a worm 13 on the shaft 38 and a worm wneel 1% on the shaft 42, and

the shaft 12 is geared to the cutter spindle 19 by spur gears 45 and 16.

As disclosed in Fig. 4 the shafts 2 1 and 33 are'interconnected through the slow speed gears 32 and 35, the gears 36 and 37 being out of mesh respectivelywith the gears 33 and 3%. If it is desired to increase the speed of the cutter 21. the gear 35 is moved to the right along shaft 38 by means of the shifting lever 17 shown in Fig. 1, which is provided with a yoke (not shown) cooperating with the grooved collar 39, whereby it is thrown out of mesh with the driving gear 5 gear 37 through the action of shifting lever {:3 upon the collar il of gear 37, is thrown 1ntomesh with-the driving gear 34. The cone 27 of clutch 22 furnishes a means for readily starting and stopping the machine and is moved into and out of engagement with the cooperating member 25 of the clutch by means of a rocker arm 49 which through a. suitable yoke (not shown) cooperates with the grooved collar 28 of the cone member 27. For enabling the clutch to be operated fromany position along the front of the machine th rocker arm 49 is connected to a horizontal bar 50slidable along the front face of the beam 6 and guided in its sliding movement by a sleeve 51 secured to the beam 6 in any suitable manner as by stud bolts 52.

When Working upon wood as in making propeller blades or when grinding a metal surface it is necessary to operate the cutter or grinder at a-much higher speed than when cutting a metal surface, and for this purpose provision is made for directly connecting the motor 16 with the cutter spindle 19 without the intermediary of transmission gears; This connection comprises a belt 53 which passes around the drum'member 25 of the clutch 22 and around the pulley 20 on the spindle 19. As the motor shaft 23 and spindle 19 are disposed at right angles to each other and in different planes it is necessary to turn the belt 53 by means of idler pulleys 54 and 55 suitably journaled on brackets 56 and 57 extending rearwardly from the beam 6. To drive the cutter by means of the belted connection the clutch 22 is thrown out and the gears 35, 36 and 37 are preferably thrown out of mesh with the gears 32, 33 and 34. In order that small cutting wheels or grinding wheels may be employed, attachments are. disclosed in Figs. 6 and 7 for driving such wheels by a geared or belted connection from the main cutter spindle 19 whereby the cutting edges'of the wheels are positioned far enough below the bottom of the beam.6 to prevent the beam from interfering with the surface of the blank which is being cut, Such wheels are especially useful in cutting concave surfaces of small radius where larger cutters would not function. In Fig. 6 a geared attachment is disclosed for driving a milling cutter. which comprises a detachable'frame 58 secured to the front face of the beam 6 by stud bolts 59 and embracing the end of the spindle 19. The frame 58 is provided with depending arms 60 and 61 terminating in bearin s 62 and 63 having bearin brasses t! P3 64 and 65. Journaled in the bearing brasses is an auxiliary cutter spindle 66 threaded upon its forward end to receive a nut 67 for clamping the cutter 68' upon the spindle. Keyed to the spindle 66 between the bearings is a pinion 69 which is'adapted to mesh with a gear'70 which may be secured to the end of thespindle 19 in lieu of the usual cutter by a nut 71 which engagesthe threaded end 2 of the spindle 19. Rotation of the main cutter spindle 19 thus transmits power to the cutter 68.

In Fig. '7 a belted attachment is disclosed which may if desired be used in lieu of the geared connection shown in Fig. 6. This attachment comprises a frame 73 secured to the face of the beam 6 by stud bolts 7 4 and embracing the end of the spindle 19. The frame is provided with a depending arm 7 5 terminating in bearings 76 and 77 having bearing brasses 78 and '79. Journaled in the bearing brasses is an auxiliary cutter spindle 80 upon the forward end of which a cut ter or grinding wheel 81 is secured by a nut 82. Ifeyed to the spindle 80 between the bearings 7 6 and 77 is a pulley 83 which is connected to a pulley 84 secured to the main spindle 19 in lieu of the usual cutter. by a belt 85. The pulley 84 is secured upon the end of the spindle 19 by a nut 71.

Positioned upon the bed casting 1 and traversable on the ways 2 is a carriage 86 provided with transversely extending guide ways 87. Traversable in the ways 87 is a table 88 for supporting material or blanks represented at B beneath the cutting tool for cutting or guiding operations thereupon. The table 88 is provided with suitable T slots '89 for enabling the blanks to be secured rigidly thereto. The table 88 may be traversed transversely of the base 1 on the ways 87 by means of a suitable feed screw (not shown) operated either by the hand wheel 90 or through suit-able gear connections from the tranverse-feed shaft 91. The entire carriage 86 with the table 88 may be traversed longitudinally along the base 1' upon the ways 2 by means of the longitudinal-feed screw 92. The feed screw 92 engages the carriage 86 through a suitable nut 93 attached thereto, and may be rotated by power means as hereinafter described or by the hand wheel 94 which is connected there to by spiral gears 95 and 96.

The feed shaft 91 and screw 92 may be driven at will from the vertical shaft 31 hereinbefore described through suitable reversing and change speed gearing. The shaft 31 extends downwardly in the plane of the trunnions 4 and is provided with a suitable universal joint at 97 to enable power to be transmitted through the shaft 31 regardless of the angular or vertical position of the beam 6 with respect to the base 1. The lower end of the shaft 31 is journaled in suitable bearings (not shown) in the base land is provided upon its lower end with a bevel gear98 which is adapted to mesh with'one or the other of two bevel gears 99 and 100 on the transmissioirshaft 101. The gears 99 and 100 arekeyed to the shaft 101 in such manner that they may slide thereon as a unit but must transmit their rotary motion to the shaft and are provided with a suitable grooved collar engaged by a yoke clearly in Fig. 0.

102 on the shaft of the reversing lever 103; When the lever 103 is in the neutral. position, as indicated in Fig. 1, the gears are entirely out of mesh and no power maybe transmitted to the feed screws. If the lever is thrown to the right or to the left the shaft 101 is thereby coupled to the shaft 31 and is driven in either one or the other direction. For convenience the lever 103 is connected by a flexible connection 104 to a horizontal operating rod 105 suitably supported upon the front of the base 1, as by a sleeve 106. The operating rod 105may if desired be equipped with adjustable stops 107 which may be engaged by a finger 108 carried by the carriage 86 for. automatically reversing the movement of shaft 101 and thereby the direction of rotation of the feed screw 92 in desired extreme longitudinal positions of the carriage 86.

The shaft 101 is provided with a cone of gears 108 which through the intermediary of gears 109, 110, 111 and 112 transmit power to the shaft 113. The gear 109 is mounted in an adjustable relation to the gears 110 and 111 whereby the gears 110 and 111 may be driven at different speeds depending upon the position of gear 109 relative to the cone of gears 108. The adjustment of gear 109 may be suitably controlled by the shifting lever 114 which may be operated through the notched opening 115 in the base 1. The speed of the shaft 11.3 may also be regulated by movement of the gear 110 out of engagement with the gear 112 and movement of gear 111 into engagement with gear.116.on shaft 113. by means of gear shift lever 117. As this gear shifting mechanism is substantially the same as cueto 'narily employed on engine and turret lathes it has been shown only diagrammatically herein and a further description thereof is considered unnecessary.

The shaft 113 is connected by gears 118 and 119 to a clutch gear 120 shown most This gear 120 is mounted upon a shifting arm 121 pivoted on the shaft of gear 119, and is adapted to mesh with either gear 122 on g the longitudinal-feed screw'92 or with the gear 123 on the trans verse-feed screw 91. Thus by depressing the lever 121 the feed screw 92 may be driven at 'variousspeeds depending upon the ad justmentofthe gear shifting-levers 114 and 117, 'andhy raising the lever 121 the feed screw 91 maybe similarly driven. For the purpose of gaining accessto the interior of the-based to inspect the gearing the end of the basoadjacent the gearing. is provided with adetachable cover plate 123 suitably storage'of tools, etc., therein.-

Traversable on the ways 3 is a template carriage 125". This carriage is traversed by the feed screw 92 but in an opposite direction to. the work carriage 86 and at three times the speed, asthe-left-hand and righthand ends of the screw 92 which respectively feed the carriage 86 and 125 are oppositely and differently pitched. By feeding the respective carriages toward and away from each other inertia forces are thus to some ex tent overcome. While the carriages are shown as arranged to be traversed in opposite directions it is apparent that they mightreadily be. fed in the same direction by suitably altering the pitch of the feed screw 92.

The template. carriage shown in detail in Figs. 8, 9, 10 and 11 is provided with a plurality of vertically disposed openings 126 in which are slidably adjustable template rods 127 and locking shoes 128. The template rodsare provided with keyways 129 in which splines 130 integrally formed on the shoes'128 engage for preventing rotation of the rods 127 i in the openings 126. The rods 127 are locked in their adjusted position by means of set screws 131 threaded through the face of carriage125 and engaging in recesses in the. faces of shoes 128, the set screws being provided upon their outer ends with handles 132 arranged as shown in Figs. 1 and 8 in two parallel rows, the handles of one row being staggered with respect to the handles of the other row. Each rod 127 terminates at its upper end in a knife-edge head 133provided upon each end with side straps 134 and 135 attached thereto by means of screws 136. Each strap is formed upon its inner surface with a downwardly turned knife-edge 137 as mostclearly shown in Fig. 11. Resting upon the the knife edges 133 and retained thereon by means of the side straps 134 and 135 and their downturned knife edges 137, is a. flexible steel template strip 138, which may be easily flexed by means of the template rods 127 to assume any desired curvature. This strip is preferablysecured at amid point between its ends to prevent it from slipping longitudinally outof the heads of the rods 127. The knife edges 137 overlap the edges only of the top surface of the template strip 138 leaving substantially the entire upper surface of the strip free for engagement by the stylus orguiding member 139.

The semi-circular guiding member 139 is attached to the end of beam 6 by means of bolts 140 which pass through slots .141in the member 139, thereby permittingja coarse adjustment of the member relativeto the beam 6. :The contacting edge or other part of the member 139 is provided with any preferred form of fine adjustment, such as a steel tape 142 fixed to the member at one endas at 143 and connectedr at its other end.

to a lever 144 pivoted to the member at 145.

Tapes 142 of different thickness may be at ing in a minute extreme the radius of the member 139 in proportion to the decrease in diameter of the cutting or grinding tool 21 as it wears down. 7

The template rods 12? are adjusted vertically within the carriage 125 by means of the micrometer screw 147 mounted vertically within the base 1 in alignment with the lower ends of the rods. The screw 147 is arranged to operate through the nut 148 and is rotated by means of a hand wheel 149 through a worm and gear connection 150 and 151. For indicating the extent of adjustment the micrometer screw is connected by suitable gearing to the indicator 152 which for example may indicate the adjustment in thousandths of an inch. To ad just the template rods they are brought in succession over the micrometer screw 147 by means of the feed screw 92 and hand wheel 94, their clamping screws 132 are'then loosened and they are then raised to the desired position as indicated upon the indicator 152 and again clamped in the adjusted position. I

A pedal 153 is connected by a link 154 to the beam 6 for the purpose of raising the beam 6 to remove the cutter and guide from the blank and template respectively. The

downward movement of the beam when re leased by the pedal may be suitably restrained by a dash pot (not shown) connected to the link 154 in any desired manner to prevent sudden impact of the cutter upon the work. For steadying the beam 6 when making heavy cuts, the slotted member 155'is provided, the member being attached to the carriage 125 by a bolt 156 and adapted to be secured to the beam 6 by a bolt 157 which passes through the slot in member 155.

The machine above described is especially adapted for cutting model aerofoils which have a uniform curvature throughout their length, as the template may be initially set and the tool guided thereby in successive adjacent cutting movements across the blank from which the aerofoil is being out. If,

however, it is desired to cut aerofoils which not only have a curvature from edge to edge or transversely of the blank but from base to tip or longitudinally of the blank, it then becomes necessary to reset the template between successive cutting operations. In Fig. 12 a modified form of the invention is diagrammatically illustrated for cutting a figured surface or surface curving both in a lateral and a longitudinal direction with a single initial setting of the template. In the machine therein illustrated both the work carriage 158 and the template carriage 159 are traversable both longitudinally and transversely under the cutting tool 21 and the guide member 139 respectively. To enable such movements the carriages 158 and 159 are mounted to be traversed on the ways 160 by a longitudinal-feed screw 161, the ways 160 being adapted to be traversed transversely on the stationary ways 162 formed upon the bed-casting or base 1. by a transverse-feed screw 163. The template 159 comprises a plurality of flexible template strips 164 disposed in parallel relation longitudinally of the carriage 159. Each template strip may be adjusted by template rods 165 in substantially the same manner as shown in Fig. 1 or in any other suitable manner. Extending transversely across the template strips 164 is a flexible templatestrip 166 with which the guide member 139 contacts. From the above description it is apparent that the flexible strip 166 assumes a curvature which varies as it is moved longitudinally along the template strips 164. If then the carriages 158 and 159 are traversed by the feed screw 161 beneath the cutter 21 and 139, the strip 166 will guide the cutter 21 across the blank B through the contact of member 139 with the strip 166. Between successive cuts the carriages are traversed by the transverse-feed screw 163 to position the member 139 and cutter 21 over successively difierent portions of the template and blank. Figs. 18 and 14 show a blank B which has been partially roughed out by successive transverse cuts of the tool 21. After being thus roughed out the blank may be readily smoothed up by removing the projecting ridges left by the cutting tool. It is .of course possible to cut the blank in final form without requiring later smoothing.

In Figs. 15 and 16 an attachment is dis closed for holding a propeller blank P in position on the table 88 underneath the cutter 21. The attachment comprises a base member 167 which may be bolted to the table 88 by means of T-bolts 168 which pass therethrough and engage in the T-slots 89 of the table. Pivotally supported upon the base 167 by a stud bolt 169 is a circular disc 170. The disc 170 is provided around its periphery with a plurality of apertures 171, preferably twenty-four in number, with which a plunger 172 carried by the base 167 is adapted to cooperate for the purpose of holding the disc in any one of a plurality of angular positions. The disc 170 is adapted to receive a propeller blank P which may beheld thereon by the central stud bolt 173, and the bolts 174 which pass through the plate 175 and the blank Pinto the disc 170. The arms of the blank which are to be cut by the cutter 21 to form the blades of the propeller may be held at their ends when positioned in the desired position for cutting by a clamp 176 secured to the table 88 by a stud-bolt 177 to prevent vibration. The blades may thus be revolved successively into position beneath the cutter so that correspondingportions of each blade may be cut with a single setting of the template.

The operation of the machine disclosed in Figs. 1, 2 and 3 is as follows: The blank B either of wood, metal or other suitable material from which it is desired to cut a model aerofoil is first secured to the table 88 in any suitable manner. The template strip 138 is then adjusted by the rods 12'? in accordance with calculated ordinates of curvature by traversing the template carried by means of hand wheel 94 to position successive template rods over the micrometer screw 1 17', which is then adjusted. After carefully adjusting the template strip the carriage 88 is traversed transversely by the hand wheel 90 to position the blank B beneath the cutter 21 in a position for the first cut and both carriages 88 and 125 are traversed longitudinally to position the blank B and template in positions beneath the cutter 21 and guide 139 for starting the cut. The cutter is then started and rotated at a speed appropriate to the nature of the material being cut by proper adjustment of the clutch lever 49 and gear shift levers 17 and 48, and the longitudinal-feed screw 92 is started for traversing the carriages by operation of the clutch lever 103 and suitable adjustment of the speed changing levers 114 and 117. Movement of the template carriage beneath the member 139 raises or lowers the beam 6 and thereby the cutter 21.. After each cut the carriage 88 may be moved transversely by the feed screw 91 or by the hand wheel 90 as desired to bring the blank B into position for another cut. If the blank is to be cut with a uniform curvature throughout its length successive cuts are taken without resetting the template. If, however, the blank B is to be cut as illustrated in Figs. 13 and 14 the template must be reset after every cut.

In order to attain great accuracy in cutting the model surfaces, the template is preferably so constructed that the coordinates of the flexible template are proportionately larger than the coordinates of the desired model surface. In the machine illustrated the cutter axis is positioned at a point on the beam 6 which is one-third the distance between the center of the guide member 189 and the axis of trunnions 4. Consequently the vertical movement of the cutter is one-' third the vertical movement of the member The template is therefore adjusted with ordinates three times the length of thecordinates of the desired model surface and the template carriage is fed beneath the member 139 at three times the speed of the work carriage.

In use, the machine in any form, such as those illustrated, may be adjusted rapidly by the successive settings of its template rods 127, or the rods 165, to scale units read off from a calculated table, drawing, or curve, and when so adjusted may be operated without requiring skill to reproduce the calculated surface predetermined by the ad justed template. To a large degree the hand work necessary heretofore in making model aerofoils and propellers in accordance with calculated specifications is avoided by practice of the method or art with the aid of apparatus such as described.

I claim:

1. A machine for forming an aerofoil surface in accordance with theoretically determined values having therein, a carriage for supporting a blank, a carriage having thereon a template adjustable in accordance with said theoretical values, an oscillatable member carrying thereon a forming tool for cutting said blank and a guiding member for cooperating with said template, and means for traversing said carriages conjunctively in opposite directions beneath said formingtool and said guiding member respectively whereby said cutting tool is caused to form the surface of said blank to conform to said determined values.

2. A machine for forming an aerofoil surface in accordance with theoretically determined values having therein, a carriage for supporting a blank, a carriage having thereon a template adjustable in accordance with said theoretical values, an oscillatable member carrying thereon a forming tool -for forming said blank and a guiding member for cooperating with said template. and a feed screw for traversing-said carriages conjunctively in opposite directions and at different speeds beneath said forming tool and said guiding member respectively whereby said forming tool iscaused to form the surface of said blank to conform to said determined values. V

3. A machine for forming irregularly curved or figured surfaces in accordance with theoretically determined values comprising an adjustable tool and a template for controlling the adjustment thereof, said template comprising a flexible template strip of substantial width and slidably adjustable rods engaging said template strip,

each of said rods being provided with a knife edge of a length substantially greater than the diameter of the rod and upon which knife edge said strip rests for flexing :said strip.

1. A machine for forming irregularly curved or figured surfaces in accordance with theoretically determined values comprising an adjustable tool and a template for controlling the adjustment thereof, said template comprising a flexible steel template strip of substantial width, and slidably adjustable rods engaging said template strip, each of said rods being provided with strips spaced for the reception of said template strip therebetween, said strips each having a downwardly directed knife edge overlying the edges of said strip for flexing said strip.

5. A machine for forming irregularly curved or figured surfaces in accordance with theoretically determined values com-- prising an adjustable tool and a template for controlling the adjustment thereof, said template comprising a flexible template strip, and slidably adjustable rods engaging said template strip, each of said rods being provided with a knife edge of a length greater than the diameter of the rod and underlying said strip said strip and a pair of spaced members provided with knife edges respectively overlying the opposite edges of said strip.

6. A machine for forming an aerofoil surface in accordance with theoretically determined values having therein, an adjustable template comprising a flexible template strip, slidably adjustable rods provided with transversely elongate knife edges for engaging and supporting said strip said rods being constructed and arranged to flex said strip to conform to said determined values, micrometer means for adjusting said rods in succession, and an indicator for indicating the amount of each .adjustment.

7. A machine for forming an aerofoil surface in accordance with theoretically determined values comprising a base member, a template carriage movably supported thereon, an adjustable template on said carriage comprising a flexible template strip, and

slidably adjustable rods for engaging said strip to flex it to conform to said deter mined values, and a micrometer screw mounted upon said base in such position as to engage said rods in succession as said carriage is moved relative to said base for adjusting said rods.

8. A machine for forming an aerofoil sur face in accordance with theoretically determined values having therein, a template, and a guiding member having a contact surface of variable contour.

9. A machine for forming an aerofoil surface in accordance with theoretically determined values having therein, a template and a semi-circular guiding member for cooperation with said template, said guiding member having a removable contact surface comprising a flexible band.

10. A machine for forming an aerofoil surface in accordance with theoretically determinal values having therein, a template and a semi-circular guiding member for cooperation with said template, said guiding member having a removable contact surface comprising a flexible steel band and means for retaining said band whereby the radius of said member may be varied.

11. A machine for forming aerofoil surfaces in accordance with theoretically determined values having therein, an adjustable template comprising a plurality of flexible template strips spaced in parallel relation, means for adjusting said strips to conform to said determined values, and a further template strip disposed transversely of said first strips and adapted to conform itself to the curvature imposed thereupon by its engagement with said first strips.

12. A machine for forming aerofoil surfaces in accordance with theoretically determined values having therein, an adjustable template comprising a plurality of flexible template strips spaced in parallel relation, means for adjusting said strips to conform to said determined values, and a further template strip disposed transversely of said first strips and movable longitudinally thereupon, said transversely disposed strip being adapted to conform itself in each of its positions to the curvature imposed thereupon by its engagement with said first strips.

Signed by me at Langley Field, Hampton, Va, this 12th day of Aug, 1919.

F. H. NORTON. 

